As the need to record directly from the brain in humans and animals has grown over the last two decades, especially in candidate patients requiring resective epilepsy surgery, so too has the need for real-time, multi- modal analysis within an implantable package. ITN Energy Systems, in collaboration with Yale University Epilepsy Program, and Ad-Tech Medical Instruments Corporation, electrode manufacturer and end-user, will bring their unique expertise in biocompatible materials and sensors, nanoscale electronics, neurosurgery, neuroscience, and manufacturing, marketing and commercialization of brain implantable electrodes to developing a next generation, implantable sensor system. The goal of this Phase I project will be to develop a multimodal depth electrode to allow us to more fully map the seizure onset area in patients. The multimodal electrode will be an enhancement of the existing Spencer depth electrode to allow recording of icEEG, pH and potassium ([K+]). Each sensor, as part of a large, addressable (multiplexed) array, will utilize a field effect transistor (FET) to transduce the electrical signal (induced surface charge) from the biological parameter of interest (i.e., ions such as hydrogen (pH) or potassium, and icEEG) into a direct and `label-free' electrical readout without the use of bound dyes or fluorescent optical probes. The sensors for these modalities will be co-localized and will all interface with conventional data collection equipment. The device will initially be tested in rats to ensure that the system is feasible for human use. A comparison of the measured pH and K+ will be made between the multimodal electrode and conventional measurements in acute and chronic in vivo studies. These rat studies will be critical in determining the refinements needed to be addressed as part of a Phase II trial aimed at using this technology in patients. Anticipated Phase 2 efforts will move the device towards use in patients as well as replace the current electrodes with completely wireless devices which can continuously and synchronously sample the specified modalities in real-time with a battery-free solution, and wirelessly transmit the measures directly to a single computer port in digital format without any intervening hardware. PUBLIC HELATH RELEVANCE: This project proposes the design and testing of a modified depth electrode to directly measure electrical activity, potassium, and pH from the brain. Such a depth electrode may expand the use of conventional depth electrodes in the localization of the seizure onset region in medically intractable epilepsy patients requiring surgery, the monitoring of brain trauma, and the understanding of other neurological disorders. The proposed battery-free semiconductor electronics based solution will facilitate integration into conventional data collection equipment to create a low cost, biocompatible diagnostic system that can be actuated and interrogated from outside the brain. [unreadable] [unreadable] [unreadable]